Vehicle suspension assembly

ABSTRACT

Large vehicles such as off-highway dump trucks provide extraordinary suspension problems due to the immense weight of the vehicles. A suspension assembly particularly useful for such vehicles includes a dual wheel set supported by an axle housing therebetween. Trunnions extend forwardly and rearwardly from the ends of the housing. The forwardly extending trunnion is received within a spherical, laminated, elastomeric, bearing element which is affixed to the vehicle frame. The rearwardly extending trunnion is similarly received within a spherical, laminated, elastomeric bearing element which is affixed to the piston member of a rigidly mounted, shock absorbing suspension strut. The bearing members permit axial, radial and vertical movement of the trunnions relative to the frame of the vehicle. An arm extends vertically from the housing and is received within a recess in the frame to restrict radial movement of the suspension assembly beyond desired limits by engagement of the arm against spaced, parallel walls which partially define the recess. Axial, lateral and vertical forces are transmitted to the frame through the forwardly positioned bearing member and the shock absorbing suspension strut.

United States Patent 1 Davis Nov. 20, 1973 VEHICLE SUSPENSION ASSEMBLY[75 Inventor: Leo W. Davis, Dallas, Tex. I Assignw .EQQMQa-E LRMQ [22]Filed: May 8, 1972 21 App]. No.: 250,946

[52] US. Cl. 280/124 A, 280/112 R, 267/65 R Primary Examiner-PhilipGoodman Assistant ExaminerJohn A. Carroll Attorney-D. Carl Richards etal.

57 ABSTRACT Large vehicles such as off-highway dump trucks provideextraordinary suspension problems due to the immense weight of thevehicles. A suspension assembly particularly useful for such vehiclesincludes a dual wheel set supported by an axle housing therebetween.Trunnions extend forwardly and rearwardly from the ends of the housing.The forwardly extending trunnion is received within a spherical,laminated, elastomeric, bearing element which is affixed to the vehicleframe. The rearwardly extending trunnion is similarly received within aspherical, laminated, elastomeric bearing element which is afiixed tothe piston member of a rigidly mounted, shock absorbing suspensionstrut. The bearing members permit axial, radial and vertical movement ofthe trunnions relative to the frame of the vehicle. An arm extendsvertically from the housing and is received within a recess in the frameto restrict radial movement of the suspension assembly beyond desiredlimits by engagement of the am against spaced, parallel walls whichpartially define the recess. Axial, lateral and vertical forces aretransmitted to the frame through the forwardly positioned bearing membetand the shock absorbing suspension strut.

16 Claims, 6 Drawing Figures PAIENTED NOV 2 0 I975 SHEET 2 SF 3 FIG? 4VEHICLE SUSPENSION ASSEMBLY This invention relates to vehicle suspensionassemblies for trucks, buses and other heavy vehicles and moreparticularly to a vehicle suspension assembly having rigidly mountedcomponents.

Technological progress and economic precepts of the day have resulted ina demand for high volume production in the mining industry. High volumeproduction requires substantial capital investments in mine haulingequipment. In many instances, the ultimate determinants in the economiclife of an open pit mine are the haulage and material handlingoperations. To bring material handling costs in line with other costs ofa mining operation improved and more reliable vehicles with larger loadcarrying capabilities become a requirement. As mine vehicles increase insize, the problems of reliability increase due primarily to increasedstresses placed on the vehicle components including the suspensionassembly.

In fact, the suspension assemblies of large mining vehicles havepresented some particularly perplexing problems of reliability. Theordinary articulated suspension assembly becomes unreliable dueprimarily to the concentration of forces from the supporting wheels tothe vehicle frame through a pivoted connection. The weak link, so tospeak becomes the pivoted connection which must be designed to withstandall the forces exerted on the wheel bogey assembly from the vehicleframe. With such systems it is also necessary to provide a lateralreaction member such as a pan hard rod or a sliding guide.

A feature of the present invention is to provide distribution of forcesbetween wheel supporting apparatus and a vehicle frame. Another featureof the invention is to provide a relatively maintenance free, rigidconnection between wheel supporting structure and the vehicle frame toimprove the reliability of vehicle suspension assemblies. This inventionutilizes a suspension strut which serves as a lateral load reactionmember and thus does not require a pan hard rod or guide. The pan hardrod type of suspension assembly has the disad vantage of requiringlateral displacement of the wheels as it swings on its bearings duringmovement of the vehicle.

The present invention can be generally described as a suspensionassembly for a vehicle having a frame and a ground engaging movablemember which permit advancement of the vehicle relative to the ground.The assembly includes a housing which supports the ground engagingmember and has first and second trunnions extending therefrom; one ofsaid trunnions extends forwardly and the other of said trunnions extendsrearwardly from said housing.

A first bearing is mounted on said first trunnion and is attached to thevehicle frame. A shock absorbing suspension strut having a first memberrigidly attached to said vehicle frame and a second member movable withrespect to said first member is also provided. A second bearing mountedon the second trunnion is attached to the second number of thesuspension strut. One of the bearings permits at least radial andvertical movement of the trunnion to which it is mounted relative to theframe and the other of said bearings permits radial, vertical and axialmovement of the trunnion to which it is mounted relative to the frame.

A more complete understanding of the invention and its advantages willbe apparent from the specification and claims and from the accompanyingdrawings illustrative of the invention.

Referring to the drawings:

FIG. 1 is a side'view of the rear bogey of avehicle showing a rigidlymounted suspension strut;

FIG. 2 is a side view of the bogey of FIG. 1 and also illustrating-arigidly mounted suspension strut;

FIG. 3 is a cross-section of a radial restraining mechanism to limit theradial movement of the housing in the suspension assembly of FIG. 2;

FIG. 4 is a side view, partially in section, of the vehicle suspensionassembly in accordance with the present invention;

FIG. 5 is a sectional view of a tubular-type spherical bearing ofelastomeric elements; and v FIG. 6 is an illustration of movement for avehicle suspension assembly employing a rigidly mounted suspensionstrut.

Referring to FIGS. 1 and 2, there is shown a suspension assembly for adual wheel set for supporting a vehicle, such as an ore carrier of thetype found in open pit mining operations.-

In a typical ore hauling vehicle, four dual wheel sets are used tosupport the vehicle. Each of the wheels (tires) 10 and 12, which areusually of a rubber composition on a steel body, are individuallypowered by electric motors. The electric motor for powering the wheel 10is located in a shroud 14 and the electric motor for powering the wheel12 is located in a shroud 16. These shrouds 14 and 16 are fastened bymeans of bolted flanges to an axle carrying housing 18. Power forenergizing the motor drive for each of the wheels 10 and 12 is typicallyprovided by a diesel-electric generator carried by the vehiclesupporting frame 20. Such control systems are conventional and a furtherdescription is not deemed necessary.

To support the frame 20 through the wheels 10 and 12, the axle carryinghousing 18 includes cylindrical trunnions 22 and 24 extending from theends thereof. The forward trunnion 22 is received within a laminatedrubber and metal bearing 26 fastened into the bearing mount 28 that isrigidlybolted to the forward leg 30 of supporting frame 20. The reartrunnion 24 extends through a rubber and metal bearing 32 which isbolted by means of a flange 34 to a bearing mount 36. The bearing 'mount36 includes a flange 38 rigidly attached to a piston 40 of a shockabsorbing, suspension strut 42 having a cylinder 44 reciprocally mountedwith respect to the piston to cooperate therewith to form a shockabsorbing, suspension member. Typically, the cylinder 44 contains adampening fluid. Suspension strut 42 may take various conventionalforms. However, the type of suspension strut illustrated in U. S. Pat.No. 3,256,005 is preferred.

An important feature of the present invention is the rigid mounting ofthe cylinder 44 to the supporting frame 20 thereby restricting thestroke of the piston 40 to always be along a fixed line, generallyindicated by the center line 46. To be more specific, as the wheels 10and 12 mounted to the axle carrying housing 18 encounter asperities inthe terrain the rear trunnion 24 will move up and down. This up and downmovement will not be longitudinal but will cause the trunnion to movealong an arc. Restraint of the front trunnion 22 causes the end of thetrunnion 24 to move through a circular arcuate path with bearing 26 asthe center of radius. Since a resilient bearing 32 is utilized betweenthe rear trunnion 24 and the bearing mount 36, radial, axial andvertical movement of the rear trunnion relative to the bearing mount 36is permitted due to the elastomeric nature of the rubber portion of thebearing 32. Thus, the cylinder44 of the suspension strut 42 may berigidly rather than pivotally mounted to the supporting frame 20 sinceany deviations of the rear trunnion 24 from a path along the line 46will be accommodated by the rear bearing 32 and the front bearing 26which also flexes axially.

As the wheels 10 and 12 traverse ridges and ruts in a road, trunnions 22and 24 will rotate within their respective bearings 26 and 32. To limitthe amount of rotational or radial movement between the trunnions andthe respective bearing, a restraining assembly 48 is provided. Thisassembly includes a protruding arm 50, as best illustrated in FIG. 3,welded or otherwise attached to the axle carrying housing 18. This arm50 extends into a recess 51 in housing 52 welded or otherwise rigidlyattached to the supporting frame 20. Encircling the housing 52 arebolsters54, 56 and 58.

As best illustrated in FIG. 3 by the dotted outline of the arm 50, therestraining assembly 48 limits the rotation of the axle carrying housing18 to i 10 of a center line position, indicated by a center line 60.Movement beyond this degree is prevented by engagement of arm 50 withthe opposite parallel walls 53 and S of housing 52.

Referring to FIG. 4, there is shown an enlarged view of the suspensionassembly including a partial section of the trunnions 22 and 24 andtheir respective bearings 26 and 32. With reference to the bearing 26,as shown enlarged in FIG. 5, it includes an outer race 62 having acylindrical outer surface and a concave spherical inner surface. Inintimate contact with the spherical surface of the outer race 62 is oneof three elastomeric elements 64 interleaved with steel spacers 66.Together, the elastomeric elements 64 and the steel spacers 66 form alaminated tubular-type spherical configuration. The innermost of theelastomeric elements 64 is adhered to an inner race 68 having a convexspherical outer surface and a cylindrical inner surface mating with theouter diameter of the rear trunnion 22. The entire bearing structure isbolted to the bearing mount 28 by means of a flange 70. To secure thebearing 26 to the trunnion 22, the inner race 68 includes an end plate72 bolted to the trunnion.

- 36. Adhered to the inner surface of the race 74 is a laminatedstructure of three elastomeric elements 76 interleaved with steelspacers 78. An inner race 80 has an outer surface mating with theinnermost elastomeric element 76 and has an inner surface mating withthe outer diameter-of the trunnion 24. The bearing 32 is bolted to thebearing mount 36 by means of a flange 82. To secure the bearing 32 tothe trunnion 24, the inner race 68 includes an end plate 34 bolted tothe trunnion and the inner race.

To provide for the normal working alignment of the longitudinal axisthrough the trunnions 22 and 24 and the longitudinal axis of the strut42, the center line 46 through the strut 42 is displaced from theperpendicular with the longitudinal axis through the trunnions 22 and 24in a static unloaded condition.

This relationship is illustrated in FIG. 6 wherein the center line 86corresponds with the same numbered center line of FIG. 4..The centerline 86 represents the position of the trunnions 22 and 24 with respectto the center line 46 of the suspension strut 42 in a staticunloadedcondition. In the static unloaded condition, the center line 86 isperpendicular to a center line through the bearing mount 28 and thecenter line through the bearing 26. Under these conditions, it will benoted that there is an angular displacement between the center line 46of the suspension strut 42 and a line 88 perpendicular to the centerline'86. Typically, the angular displacement between the center line 46and the perpendicular 88 is 2.

With a normal static load on the vehicle, the trunnions 22 and 24 movewith respect to the associated bearing housings 28 and 36, respectively.This condition is illustrated in FIG. 6 wherein the longitudinal axisthrough the trunnions 22 and 24 is indentified by the reference numeral86a. In this position of the trunnions 22 and 24 with respect to thesuspension strut 42, a right angle relationship exists between thecenter line 86a and the center line 46. I

Typically, the longitudinal axis through the trunnions '22 and 24 movesvertically slightly in excess of 2 between a static unloaded conditionand a static loaded condition. As the vehicle traverses ridges and rutsthe entire bogey assembly moves about the bearing 26 of the fronttrunnion 22. This causes vertical displacement between the piston 40 andthe cylinder 44 and rotation of the rear trunnion 25 within the bearingmount 36. Typically, the longitudinal axis through the trunnions 22 and24 rotates from 3 to 4' from the static unloaded position.

The front and rear bearings 26 and 32, respectively, permit radial,vertical and axial movement of the trunnions 22 and 24 relative to theframe 20. Radial displacement is limited, as explained before, bytherestraining assembly 48. Vertical movement of front trunnion 22 isslight, but permits movement of piston member 40 within cylinder 44. Aspiston 40 moves upwardly the lower portion of the front and upperportion of the rear of bearing 26 will be put in compression while theupper portion of the front and lower portion of the rear of bearing 26will be put in tension by the vertical movement of trunnion 22. Thedegree of axial movement of trunnions 22 and 24 relative to frame 20will depend not only upon the position of piston 40 relative to cylinder44, as explained above, but also the dynamic motion of the vehicle. Forexample, if the vehicle is accelerating while the piston 40 is movingupwardly or downwardly past line 86a (FIG. '6) the forces tending todisplace trunnion v 22 rearwardly will be counteracted. Conversely, ifthe vehicle is decelerating the axial force tending to move trunnion22'rearwardly willaccentuate the rearward force arising from the upwardor downward movement of piston 40 past line 86a. Conversely, the forcesacting on rear bearing 32 when piston 40 strokes past line 86a in eitherdirection are accentuated by acceleration and counteracted bydeceleration.

While bearing members having an elastomeric element are preferred othertypes of bearings may be used so long as they permit at least radial andvertical freedom at one of the trunnions and radial, vertical and axialfreedom at the other trunnion.

While only one embodiment of the invention, together with modificationsthereof, has been described in detail herein and shown in theaccompanying drawings, it will be evident that various modifications arepossible without departing from the scope of the invention.

What is claimed is:

l. A suspension assembly for a vehicle having a frame and a groundengaging movable member which permit advancement of the vehicle relativeto the ground, which assembly comprises:

a housing which supports the ground engaging member and has first andsecond trunnions extending therefrom, one of said trunnions extendingforwardly and the other of said trunnions extending rearwardly from saidhousing;

a first bearing mounted on said first trunnion and attached to thevehicle frame;

a shock absorbing, suspension stmt having a first member rigidlyattached to said vehicle frame and a second member movable with respectto said first member; and

a second bearing mounted on said second trunnion and attached to thesecond member of the suspension strut, one of said bearings permittingat least radial and vertical movement of the trunnion to which it ismounted relative to the frame and the other of said bearings permittingradial, vertical and axial movement of the trunnion to which it ismounted relative to the frame.

2. The assembly of claim 1, wherein both of said bearing members permitradial, vertical and axial movement of the trunnion to which it ismounted relative to the frame.

3. The assembly of claim 2, wherein the bearing members include adistortable material.

4. The assembly of claim 3, wherein said bearing members includespherical laminated outer elementsand a tubular inner race.

5. A suspension assembly for a vehicle having a supporting framecomprising:

an axle carrying member for supporting wheels on said vehicle and havingfirst and second trunnions extending therefrom in a substantiallyaligned posi tion;

a first bearing comprising a distortable material mounted to the firsttrunnion and attached to the supporting frame;

a supenstion strut having a first member rigidly attached to thesupporting frame and a second member movable with respect to the firstmember; and

a second bearing comprising a distortable material mounted to the secondtrunnion and attached to the second member of said suspension strutv 6.A suspension assembly for a vehicle having a supporting frame as setforth in claim 5, wherein said first and second bearings includelaminated elastomeric elements.

7. A suspension assembly for a vehicle having a supporting frame as setforth in claim 6, wherein said elements have a tubular-type sphericalconfiguration.

8. A suspension assembly for a vehicle having a supporting frame as setforth in claim 5, wherein said suspension strut includes a cylindricalmember containing a dampening element and a piston member movable withrespect to said cylindrical member.

9. A suspension assembly for a vehicle having a supporting frame as setforth in claim 5, wherein said suspension strut includes a cylindricalfirst member rigidly attached to the supporting frame and filled with adampening fluid and a piston second member movable with respect to saidcylindrical member and attached to the second bearing.

10. A suspension assembly for a vehicle having a supporting frame as setforth in claim 9, wherein said cylindrical first number is rigidlymounted to the supporting frame at an angle with respect to alongitudinal axis extending through the first trunnion of said axlecarrying member.

1 l. A suspension assembly for a vehicle having a supporting framecomprising:

an axle carrying member for supporting wheels of said vehicle and havingfirst and second trunnions extending therefrom in a substantiallyaligned position;

a first tubular-type spherical bearing of laminated elastomeric elementsmounted to the first trunnion and attached to the supporting frame;

a suspension strut having a cylindrical member rigidly attached to thesupporting frame and filled with a dampening fluid and a piston secondmember movable with respect to the cylindrical member; and

a second tubular-type spherical bearing of laminated elastomericelements mounted to the second trunnion and attached to the pistonmember of the suspension strut.

12. A suspension assembly for a vehicle having a supporting frame as setforth in claim 11, wherein said cylindrical first member is rigidlymounted to the supporting frame at an angle with respect to alongitudinal axis extending through the first trunnion.

13. A suspension assembly for a vehicle having a supporting framecomprising:

an axle carrying member for supporting wheels of said vehicle and havingfirst and second trunnions extending therefrom in a substantiallyaligned position;

a first bearing comprising a distortable material mounted to the firsttrunnion and attached to the supporting frame;

a suspension strut having a first member rigidly at-- tached to saidsupporting frame and a second member movable with respect to the firstmember;

a second bearing comprising a distortable material mounted to the secondtrunnion and attached to the second member of said coupler means; andrestraining means between said axle carrying member and the supportingframe to restrict the radial movement of the former with respect to thelatter.

14. A suspension assembly for a vehicle having a supporting frame as setforth in claim 13, wherein said first and second bearings includelaminated elastomeric elements of a tubular-type sphericalconfiguration.

15. A suspension assembly for a vehicle having a sup porting frame asset forth in claim 14, wherein said suspension strut includes acylindrical first member rigidly attached to the supporting frame andfilled with a dampening fluid and a piston second member movable withrespect to the cylindrical member and attached to said second bearing.

16. A suspension assembly for a vehicle having a supporting frame as setforth in claim 15 wherein the cylindrical first member is rigidlymounted to the supporting frame at an angle with respect to alongitudinal axis extending through the first trunnion. k k

1. A suspension assembly for a vehicle having a frame and a groundengaging movable member which permit advancement of the vehicle relativeto the ground, which assembly comprises: a housing which supports theground engaging member and has first and second trunnions extendingtherefrom, one of said trunnions extending forwardly and the other ofsaid trunnions extending rearwardly from said housing; a first bearingmounted on said first trunnion and attached to the vehicle frame; ashock absorbing, suspension strut having a first member rigidly attachedto said vehicle frame and a second member movable with respect to saidfirst member; and a second bearing mounted on said second trunnion andattached to the second member of the suspension strut, one of saidbearings permitting at least radial and vertical movement of thetrunnion to which it is mounted relative to the frame and the other ofsaid bearings permitting radial, vertical and axial movement of thetrunnion to which it is mounted relative to the frame.
 2. The assemblyof claim 1, wherein both of said bearing members permit radial, verticaland axial movement of the trunnion to which it is mounted relative tothe frame.
 3. The assembly of claim 2, wherein the bearing membersinclude a distortable material.
 4. The assembly of claim 3, wherein saidbearing members include spherical laminated outer elements and a tubularinner race.
 5. A suspension assembly for a vehicle having a supportingframe comprising: an axle carrying member for supporting wheels on saidvehicle and having first and second trunnions extending therefrom in asubstantially aligned position; a first bearing comprising a distortablematerial mounted to the first trunnion and attached to the supportingframe; a supenstion strut having a first member rigidly attached to thesupporting frame and a second member movable with respect to the firstmember; and a second bearing comprising a distortable material mountedto the second trunnion and attached to the second member of saidsuspension strut.
 6. A suspension assembly for a vehicle having asupporting frame as set forth in claim 5, wherein said first and secondbearings include laminated elastomeric elements.
 7. A suspensionassembly for a vehicle having a supporting frame as set forth in claim6, wherein said elements have a tubular-type spherical configuration. 8.A suspension assembly for a vehicle having a supporting frame as setforth in claim 5, wherein said suspension strut includes a cylindricalmember containing a dampening element and a piston member movable withrespect to said cylindrical member.
 9. A suspension assembly for avehicle having a supporting frame as set forth in claim 5, wherein saidsuspension strut includes a cylindrical first member rigidly attached tothe supporting frame and filled with a dampening fluid and a pistonsecond member movable with respect to said cylindrical member andattached to the second bearing.
 10. A suspension assembly for a vehiclehaving a supporting frame as set forth in claim 9, wherein saidcylindrical first number is rigidly mounted to the supporting frame atan angle with respect to a longitudinal axis extending through the firsttrunnion of said axle carrying member.
 11. A suspension assembly for avehicle having a supporting frame comprising: an axle carrying memberfor supporting wheels of said vehicle and having first and secondtrunnions extending therefrom in a substantially aligned position; afirst tubular-type spherical bearing of laminated elastomeric elementsmounted to the first trunnion and attached to the supporting frame; asuspension strut having a cylindrical member rigidly attached to thesupporting frame and filled with a dampening fluid and a piston secondmember movable with respect to the cylindrical member; and a secondtubular-type spherical bearing of laminated elastomeric elements mountedto the second trunnion and attached to the piston member of thesuspension strut.
 12. A suspension assembly for a vehicle having asupporting frame as set forth in claim 11, wherein said cylindricalfirst member is rigidly mounted to the supporting frame at an angle wIthrespect to a longitudinal axis extending through the first trunnion. 13.A suspension assembly for a vehicle having a supporting framecomprising: an axle carrying member for supporting wheels of saidvehicle and having first and second trunnions extending therefrom in asubstantially aligned position; a first bearing comprising a distortablematerial mounted to the first trunnion and attached to the supportingframe; a suspension strut having a first member rigidly attached to saidsupporting frame and a second member movable with respect to the firstmember; a second bearing comprising a distortable material mounted tothe second trunnion and attached to the second member of said couplermeans; and restraining means between said axle carrying member and thesupporting frame to restrict the radial movement of the former withrespect to the latter.
 14. A suspension assembly for a vehicle having asupporting frame as set forth in claim 13, wherein said first and secondbearings include laminated elastomeric elements of a tubular-typespherical configuration.
 15. A suspension assembly for a vehicle havinga supporting frame as set forth in claim 14, wherein said suspensionstrut includes a cylindrical first member rigidly attached to thesupporting frame and filled with a dampening fluid and a piston secondmember movable with respect to the cylindrical member and attached tosaid second bearing.
 16. A suspension assembly for a vehicle having asupporting frame as set forth in claim 15 wherein the cylindrical firstmember is rigidly mounted to the supporting frame at an angle withrespect to a longitudinal axis extending through the first trunnion.